Link 16 Time Base Shift for Satellite Range Communication
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Link 16 communication systems face challenges in maintaining accurate time synchronization and message exchange at extreme ranges, such as satellite distances, due to propagation delays and limitations in existing link budgets and timing systems.
Innovation Solution
The solution involves modifying Link 16 terminals to align their time slots with satellite ephemeris data, shifting the time slot boundary by calculated propagation delays to accommodate extended ranges, and using advanced antenna configurations to maintain communication without modifying the legacy messaging protocol, allowing for dual time base synchronization with GPS time.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If Link 16 terminals use standard time slot alignment for message exchange, then communication works within 300 NM range, but message exchange fails at extreme ranges (satellite distances) due to propagation delays
Solution Approach 1:
The patent applies dynamics by making the time slot alignment dynamic rather than fixed. The receiving terminal calculates propagation delay based on satellite ephemeris data and dynamically adjusts its time slot alignment accordingly. This allows the system to adapt to varying ranges from terrestrial to satellite distances while maintaining reliable message exchange.
Solution Approach 2:
The patent changes the time slot alignment parameter based on propagation delay calculations. By modifying the time slot boundary offset using satellite position data, the system accommodates extreme ranges without requiring changes to the legacy messaging protocol or terminal hardware.
2Measurement precision
If Link 16 terminals synchronize to a common time base, then time synchronization accuracy is maintained, but propagation delays at satellite distances cause time slot misalignment
Solution Approach 1:
The patent applies preliminary action by having the receiving terminal pre-calculate the propagation delay using satellite ephemeris data before message exchange. This allows the terminal to proactively adjust its time slot alignment to compensate for the known propagation delay, preventing time slot misalignment rather than reacting to it after occurrence.
Solution Approach 2:
The system uses satellite ephemeris data as feedback to continuously adjust time slot alignment. The receiving terminal monitors satellite position and recalculates propagation delay to maintain accurate time synchronization despite varying ranges and propagation conditions.
Data Source
AI summary
An approach for transmitting and receiving Link 16 messages for long ranges and includes a Link 16 terrestrial transmitter, a Link 16 satellite receiver including an antenna, and a controller. The approach aligns the antenna to the Link 16 terrestrial transmitter to determine a minimum distance to an area of interest of the Link 16 terrestrial transmitter, thereby estimating a range of a link from the Link 16 terrestrial transmitter to the Link 16 satellite receiver. From the range, calculating the message propagation time. Providing a second, shifted, time slot at the Link 16 satellite, shifted by the message propagation time. Processing the signal from the Link 16 terrestrial transmitter in the second, shifted, time slot to produce a message from the Link 16 terrestrial transmitter, and presenting the message to a host.